Twisted pair and fiber optic are the two current cabling standards used to connect computers: ·Twisted-pair cable consists of strands of copper wire. This is the industry standard in new installations. There are several international standards for twisted-pair cable. Unshielded twisted-pair category 3 (UTP Cat 3) is used for phone wires, whereas Cat 5e is the most popular category for networking because it can support data transmission of up to 1000 Mbps. Cat 6 and Cat 7 are also available. ·Fiber-optic cable, made of high-quality glass strands, uses light pulses instead of electricity to carry data. However, it is the most expensive form of cable and typically used only for connecting larger networks. A wireless infrastructure for networking the machines is also possible. The following are salient issues to consider for wireless networking:
For implementing the SOL technology initiative, phone service may be needed in the testing location for contacting the NCS Pearson help desk during a test administration. Testing locations in each school should be evaluated to determine if they have sufficient electrical outlets and network jacks.
For wireless technology, use the best available transmission standard (802.11a/b/g/i) and segment the LAN as much as possible. Wireless LAN implementations should utilize the highest number of possible and/or practical security keys, with an encryption protocol to encrypt data; security keys should be changed from their default values. Currently, there are three encryption protocols to consider: Wired Equivalent Privacy (WEP), WiFi Protected Access (WPA), and WPA2. WPA2 is the latest implementation of WPA. All three protocols provide security by encrypting data over radio waves, protecting the data as it is transmitted from one end point to another. WPA2 offers stronger data protection and network access control than the two alternate security standards. Virtual Private Network (VPN) software ensures proper authentication of wireless devices/users.
For more information, review the state procurement contracts for wireless LAN infrastructure on the VITA Supply Chain Management Web page at http://www.vita.virginia.gov/procurement/contractSearch.cfm?mode=keyword.
There are four network standards for connecting computers and data transfer via an Ethernet network. Table 3 describes these network standards. Ethernet provides a fast network at a reasonable cost. Most modern computers are supplied with an integrated Ethernet interface or can easily accommodate an Ethernet network interface card.
Table 3. Network Standards
Network Standards
Ethernet (10 Mbps)
The Ethernet standard is rarely used today due to its low data capacity. Since the late 1990s, it has been replaced increasingly by 100 Mbps and Gigabit Ethernet.
Fast Ethernet (100 Mbps)
The Fast Ethernet standard supports data transfer rates of up to 100 Mbps. Fast Ethernet is the most common Ethernet standard in computer networks today. The main topology is called 100BASE-T. Although newer and faster than 10 Mbps Ethernet, it is essentially the same. The 100BASE-T topology is subdivided into the following:
100BASE-FX: 100 Mbps Ethernet over optical fiber
Note: Most 100 Mbps network switches support both 10 and 100 Mbps standards to ensure backward compatibility (commonly called 10/100 Network switch).
Gigabit Ethernet (1000 Mbps)
Gigabit Ethernet is the current standard that networking equipment companies endorse for desktop computers. Its most common use is in connections between network servers and network switches. The widely used Gigabit Ethernet is subdivided into the following:
1000BASE-T: 1 Gbps over Cat 5e or Cat 6 copper cabling
1000BASE-SX: 1 Gbps over multimode fiber (up to 550m)
1000BASE-LX: 1 Gbps over multimode fiber (up to 550m)—optimized for longer distances (up to 10km) over single-mode fiber
1000BASE-LH: 1 Gbps over single-mode fiber (up to 100km)—a long-distance solution
10 Gigabit Ethernet (10,000 Mbps)
10 Gigabit Ethernet is considered the new choice for enterprise network infrastructures. The 10 Gigabit Ethernet standard uses seven different media types for LAN, WAN, and MAN (Metropolitan Area Network). It is currently specified by the supplementary standard IEEE 802.3ae and will be incorporated into a future revision of the IEEE 802.3 standard.
· Twisted-pair cable consists of strands of copper wire. This is the industry standard in new installations. There are several international standards for twisted-pair cable. Unshielded twisted-pair category 3 (UTP Cat 3) is used for phone wires, whereas Cat 5e is the most popular category for networking because it can support data transmission of up to 1000 Mbps. Cat 6 and Cat 7 are also available.
· Fiber-optic cable, made of high-quality glass strands, uses light pulses instead of electricity to carry data. However, it is the most expensive form of cable and typically used only for connecting larger networks.
A wireless infrastructure for networking the machines is also possible. The following are salient issues to consider for wireless networking:
For more information, review the state procurement contracts for wireless LAN infrastructure on the VITA Supply Chain Management Web page at http://www.vita.virginia.gov/procurement/contractSearch.cfm?mode=keyword.
There are four network standards for connecting computers and data transfer via an Ethernet network. Table 3 describes these network standards. Ethernet provides a fast network at a reasonable cost. Most modern computers are supplied with an integrated Ethernet interface or can easily accommodate an Ethernet network interface card.
Table 3. Network Standards
Note: Most 100 Mbps network switches support both 10 and 100 Mbps standards to ensure backward compatibility (commonly called 10/100 Network switch).